I've used Logonerds a few times and overall I have been pleased.
My suggestion is to have a really good idea of what you want before you submit for their services because they are more about creating the logo than offering up ideas.
Logonerds is often brought up on the boards. I suggest you look for many threads through the use of the Search feature in the upper right hand corner of the site.
Here's one such thread
but there are many more discussions.